* fix: prevent session-emptying crash on resume commands
* docs: fix stale docstrings in goto=None crash tests and patch
- Correct checkpoint corruption claim: the error state replaces the
previous conversation state (messages: [], files: {}), it IS corrupted.
- Replace WebUI-specific language with UI-agnostic wording.
- Remove references to uncommitted local notes files.
- Add upstream issue reference (langchain-ai/langgraph#5656).
* fix: wrap _control_branch instead of reimplementing, use dataclasses.replace, add END routing and session preservation tests
* fix: rebind map_cmd on already-loaded consumers, rewrite crash-path tests to exercise __start__ via checkpoint deletion
jfilipiuk